Packard Forum Index » V-8 (1955-56)

My newly acquired Executive hardtop is running a bit rougher than the Esquire so I decided it was time for a minor electrical tuneup. The car has not been licensed since 1982, so the Champion H14Y plugs in it are probably at least that old. I went to the Parts X-Ref and shopped all of the in stock plugs with those numbers at my local NAPA store. They had only the NGK and Autolite numbers behind the counter, but showed pictures of both the Bosch and AC on the parts counter monitor. There was no availability of the H14y Champions, either by pictures or by touch. The new plugs appear to have correct threads but the threaded shaft is almost twice as long as the old ones. I am reluctant to even try them for fear that they may extend too far into the combustion chamber and cause interferance. Has anyone used these referenced plugs with the longer threaded shafts? NAPA was willing to special order the H14Y plugs from the distributor, but there's no assurance as to the same threaded shaft length as the old ones I have in the engine. I'd rather stop work until I hear from other V8 owner mechanics.

Worse thing about using a longer thread is, the threaded portion sticking out in the combustion chamber can build up "soot" and make them hard to remove later down the road.
John

AC 45 XLS. Might be ble to use 44XLS. DO NOT use anything 43 or lower in AC plugs unless u live in the Mojave desert or high speed racing.

The 45XLS is a 3/4" thread, for 56 V8's. 55 used a 7/16" thread. (someone double chek me on that).

I'm running 45XLS in my 56 Executive for ovver 15K miles and 7 yearss now.

If u come back and say u have to have Champions or NGK or somekind of a high tek platinum cooated plug then all i can say is
"ok guy".

Also, DOUBLE CHECCK to make sure the engine has 56 heads.
If it has 55 heads then that mite b why there were 7/16 thread plugs in it when u got it.

Stick some thing in the spark plug hole and measure how longgg the head is tapped.

Has anyone tried the E-3 plugs that are advertised all over the REVN TV channel. I see they even have some in 10mm size but don't know if the long reach would fit in a L8 Packard. With the multiple electrodes and claim of increased efficiency under adverse conditions, if they would fit I wonder if they would make any difference with a marginal 6v ignition.

Cap the "multiple electrode" be GAPPED???

Such plugs have been used iin Aviation engines for many decades. But i don't think they can be gapped. I'm Not real familiar with the Av. plugs otherwise.

And then u would have to figure out what HEAT RANGE of plug to use on the "multiple electrode" plugs. If theyy are actualy Aviation plugs then most likely a very HOT plug, mayb no heat ranges available for automotive use. I don't know. Just guessing.

Autolite 66.

Champion RN14YC.

Of the two I far prefer the Autolite.

Good question and I don't know if they can be gapped to the .025 or so number needed on 6v. I just happened to see one of the shows promoting the heck out of them for an engine on a clunker that was prone to fouling. Thought of Packards and the sometimes weak sparks with 6v.

IIRC my 56 Executive had Autolite 66 in it when i got it. They ran just fine too for about 12K miles or so.

I would simply avoid Champion unless u can get OLD STOCK Champion plugs from the 50's 60's or maaybe early 1970's.